Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 319 insertions, 0 deletions

diff --git a/fs/ubifs/shrinker.c b/fs/ubifs/shrinker.c
new file mode 100644
index 000000000..d00a6f20a
--- /dev/null
+++ b/fs/ubifs/shrinker.c
@@ -0,0 +1,319 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file implements UBIFS shrinker which evicts clean znodes from the TNC
+ * tree when Linux VM needs more RAM.
+ *
+ * We do not implement any LRU lists to find oldest znodes to free because it
+ * would add additional overhead to the file system fast paths. So the shrinker
+ * just walks the TNC tree when searching for znodes to free.
+ *
+ * If the root of a TNC sub-tree is clean and old enough, then the children are
+ * also clean and old enough. So the shrinker walks the TNC in level order and
+ * dumps entire sub-trees.
+ *
+ * The age of znodes is just the time-stamp when they were last looked at.
+ * The current shrinker first tries to evict old znodes, then young ones.
+ *
+ * Since the shrinker is global, it has to protect against races with FS
+ * un-mounts, which is done by the 'ubifs_infos_lock' and 'c->umount_mutex'.
+ */
+
+#include "ubifs.h"
+
+/* List of all UBIFS file-system instances */
+LIST_HEAD(ubifs_infos);
+
+/*
+ * We number each shrinker run and record the number on the ubifs_info structure
+ * so that we can easily work out which ubifs_info structures have already been
+ * done by the current run.
+ */
+static unsigned int shrinker_run_no;
+
+/* Protects 'ubifs_infos' list */
+DEFINE_SPINLOCK(ubifs_infos_lock);
+
+/* Global clean znode counter (for all mounted UBIFS instances) */
+atomic_long_t ubifs_clean_zn_cnt;
+
+/**
+ * shrink_tnc - shrink TNC tree.
+ * @c: UBIFS file-system description object
+ * @nr: number of znodes to free
+ * @age: the age of znodes to free
+ * @contention: if any contention, this is set to %1
+ *
+ * This function traverses TNC tree and frees clean znodes. It does not free
+ * clean znodes which younger then @age. Returns number of freed znodes.
+ */
+static int shrink_tnc(struct ubifs_info *c, int nr, int age, int *contention)
+{
+	int total_freed = 0;
+	struct ubifs_znode *znode, *zprev;
+	time64_t time = ktime_get_seconds();
+
+	ubifs_assert(c, mutex_is_locked(&c->umount_mutex));
+	ubifs_assert(c, mutex_is_locked(&c->tnc_mutex));
+
+	if (!c->zroot.znode || atomic_long_read(&c->clean_zn_cnt) == 0)
+		return 0;
+
+	/*
+	 * Traverse the TNC tree in levelorder manner, so that it is possible
+	 * to destroy large sub-trees. Indeed, if a znode is old, then all its
+	 * children are older or of the same age.
+	 *
+	 * Note, we are holding 'c->tnc_mutex', so we do not have to lock the
+	 * 'c->space_lock' when _reading_ 'c->clean_zn_cnt', because it is
+	 * changed only when the 'c->tnc_mutex' is held.
+	 */
+	zprev = NULL;
+	znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, NULL);
+	while (znode && total_freed < nr &&
+	       atomic_long_read(&c->clean_zn_cnt) > 0) {
+		int freed;
+
+		/*
+		 * If the znode is clean, but it is in the 'c->cnext' list, this
+		 * means that this znode has just been written to flash as a
+		 * part of commit and was marked clean. They will be removed
+		 * from the list at end commit. We cannot change the list,
+		 * because it is not protected by any mutex (design decision to
+		 * make commit really independent and parallel to main I/O). So
+		 * we just skip these znodes.
+		 *
+		 * Note, the 'clean_zn_cnt' counters are not updated until
+		 * after the commit, so the UBIFS shrinker does not report
+		 * the znodes which are in the 'c->cnext' list as freeable.
+		 *
+		 * Also note, if the root of a sub-tree is not in 'c->cnext',
+		 * then the whole sub-tree is not in 'c->cnext' as well, so it
+		 * is safe to dump whole sub-tree.
+		 */
+
+		if (znode->cnext) {
+			/*
+			 * Very soon these znodes will be removed from the list
+			 * and become freeable.
+			 */
+			*contention = 1;
+		} else if (!ubifs_zn_dirty(znode) &&
+			   abs(time - znode->time) >= age) {
+			if (znode->parent)
+				znode->parent->zbranch[znode->iip].znode = NULL;
+			else
+				c->zroot.znode = NULL;
+
+			freed = ubifs_destroy_tnc_subtree(c, znode);
+			atomic_long_sub(freed, &ubifs_clean_zn_cnt);
+			atomic_long_sub(freed, &c->clean_zn_cnt);
+			total_freed += freed;
+			znode = zprev;
+		}
+
+		if (unlikely(!c->zroot.znode))
+			break;
+
+		zprev = znode;
+		znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, znode);
+		cond_resched();
+	}
+
+	return total_freed;
+}
+
+/**
+ * shrink_tnc_trees - shrink UBIFS TNC trees.
+ * @nr: number of znodes to free
+ * @age: the age of znodes to free
+ * @contention: if any contention, this is set to %1
+ *
+ * This function walks the list of mounted UBIFS file-systems and frees clean
+ * znodes which are older than @age, until at least @nr znodes are freed.
+ * Returns the number of freed znodes.
+ */
+static int shrink_tnc_trees(int nr, int age, int *contention)
+{
+	struct ubifs_info *c;
+	struct list_head *p;
+	unsigned int run_no;
+	int freed = 0;
+
+	spin_lock(&ubifs_infos_lock);
+	do {
+		run_no = ++shrinker_run_no;
+	} while (run_no == 0);
+	/* Iterate over all mounted UBIFS file-systems and try to shrink them */
+	p = ubifs_infos.next;
+	while (p != &ubifs_infos) {
+		c = list_entry(p, struct ubifs_info, infos_list);
+		/*
+		 * We move the ones we do to the end of the list, so we stop
+		 * when we see one we have already done.
+		 */
+		if (c->shrinker_run_no == run_no)
+			break;
+		if (!mutex_trylock(&c->umount_mutex)) {
+			/* Some un-mount is in progress, try next FS */
+			*contention = 1;
+			p = p->next;
+			continue;
+		}
+		/*
+		 * We're holding 'c->umount_mutex', so the file-system won't go
+		 * away.
+		 */
+		if (!mutex_trylock(&c->tnc_mutex)) {
+			mutex_unlock(&c->umount_mutex);
+			*contention = 1;
+			p = p->next;
+			continue;
+		}
+		spin_unlock(&ubifs_infos_lock);
+		/*
+		 * OK, now we have TNC locked, the file-system cannot go away -
+		 * it is safe to reap the cache.
+		 */
+		c->shrinker_run_no = run_no;
+		freed += shrink_tnc(c, nr, age, contention);
+		mutex_unlock(&c->tnc_mutex);
+		spin_lock(&ubifs_infos_lock);
+		/* Get the next list element before we move this one */
+		p = p->next;
+		/*
+		 * Move this one to the end of the list to provide some
+		 * fairness.
+		 */
+		list_move_tail(&c->infos_list, &ubifs_infos);
+		mutex_unlock(&c->umount_mutex);
+		if (freed >= nr)
+			break;
+	}
+	spin_unlock(&ubifs_infos_lock);
+	return freed;
+}
+
+/**
+ * kick_a_thread - kick a background thread to start commit.
+ *
+ * This function kicks a background thread to start background commit. Returns
+ * %-1 if a thread was kicked or there is another reason to assume the memory
+ * will soon be freed or become freeable. If there are no dirty znodes, returns
+ * %0.
+ */
+static int kick_a_thread(void)
+{
+	int i;
+	struct ubifs_info *c;
+
+	/*
+	 * Iterate over all mounted UBIFS file-systems and find out if there is
+	 * already an ongoing commit operation there. If no, then iterate for
+	 * the second time and initiate background commit.
+	 */
+	spin_lock(&ubifs_infos_lock);
+	for (i = 0; i < 2; i++) {
+		list_for_each_entry(c, &ubifs_infos, infos_list) {
+			long dirty_zn_cnt;
+
+			if (!mutex_trylock(&c->umount_mutex)) {
+				/*
+				 * Some un-mount is in progress, it will
+				 * certainly free memory, so just return.
+				 */
+				spin_unlock(&ubifs_infos_lock);
+				return -1;
+			}
+
+			dirty_zn_cnt = atomic_long_read(&c->dirty_zn_cnt);
+
+			if (!dirty_zn_cnt || c->cmt_state == COMMIT_BROKEN ||
+			    c->ro_mount || c->ro_error) {
+				mutex_unlock(&c->umount_mutex);
+				continue;
+			}
+
+			if (c->cmt_state != COMMIT_RESTING) {
+				spin_unlock(&ubifs_infos_lock);
+				mutex_unlock(&c->umount_mutex);
+				return -1;
+			}
+
+			if (i == 1) {
+				list_move_tail(&c->infos_list, &ubifs_infos);
+				spin_unlock(&ubifs_infos_lock);
+
+				ubifs_request_bg_commit(c);
+				mutex_unlock(&c->umount_mutex);
+				return -1;
+			}
+			mutex_unlock(&c->umount_mutex);
+		}
+	}
+	spin_unlock(&ubifs_infos_lock);
+
+	return 0;
+}
+
+unsigned long ubifs_shrink_count(struct shrinker *shrink,
+				 struct shrink_control *sc)
+{
+	long clean_zn_cnt = atomic_long_read(&ubifs_clean_zn_cnt);
+
+	/*
+	 * Due to the way UBIFS updates the clean znode counter it may
+	 * temporarily be negative.
+	 */
+	return clean_zn_cnt >= 0 ? clean_zn_cnt : 1;
+}
+
+unsigned long ubifs_shrink_scan(struct shrinker *shrink,
+				struct shrink_control *sc)
+{
+	unsigned long nr = sc->nr_to_scan;
+	int contention = 0;
+	unsigned long freed;
+	long clean_zn_cnt = atomic_long_read(&ubifs_clean_zn_cnt);
+
+	if (!clean_zn_cnt) {
+		/*
+		 * No clean znodes, nothing to reap. All we can do in this case
+		 * is to kick background threads to start commit, which will
+		 * probably make clean znodes which, in turn, will be freeable.
+		 * And we return -1 which means will make VM call us again
+		 * later.
+		 */
+		dbg_tnc("no clean znodes, kick a thread");
+		return kick_a_thread();
+	}
+
+	freed = shrink_tnc_trees(nr, OLD_ZNODE_AGE, &contention);
+	if (freed >= nr)
+		goto out;
+
+	dbg_tnc("not enough old znodes, try to free young ones");
+	freed += shrink_tnc_trees(nr - freed, YOUNG_ZNODE_AGE, &contention);
+	if (freed >= nr)
+		goto out;
+
+	dbg_tnc("not enough young znodes, free all");
+	freed += shrink_tnc_trees(nr - freed, 0, &contention);
+
+	if (!freed && contention) {
+		dbg_tnc("freed nothing, but contention");
+		return SHRINK_STOP;
+	}
+
+out:
+	dbg_tnc("%lu znodes were freed, requested %lu", freed, nr);
+	return freed;
+}